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0. P. E n. Chron omet er Ecapement.

Patented April 7, 1868.

NJErERi KOTOMTMOGRAPNER, WASHINGTON. D. C.

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peers ,Patent 1%.- 76,346, dated A' n'l' 7, 1868.

IMPROVEMENT IN cHBoNoMETsR-Escus isms.

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7 Be it known that I, GEORGE'P. READ, of Boston, in the county of Suffolk, and State of Massachusetts,

have invented a new and useful Modeof Applying the Lifting or Feather-Spring to the Detent-Lever of a Ghronometer-Escapement; anddo hereby deolare the following to be a full,-clear, and exact description thereof, dueireference being had to the accompanying drawings, inaking part of this specification, and in which I Figure I is a top view or face representation,

Figure 2 an edge elevation, A I I v v l Figure 3 a .vertical and transverse section of a chronome'tereescapement detest-lever, 'showingthe applica t'ron'of my invention thereto, the said figures being made upon anenlarged-scale, the more clearly to show such invention. D

Figure 4 is a representation of a feather-spring as heretofore constructed. I

The mode heretofore practised, tola great extent, in applying the lifting-spring to the detent lever-in chronometer-escapemeuts, has been to form the spring with an enlargement upon one end, this enlargement having an elongated slot madein it, throngh which a screw passes and is screwed into the detent-lever', the head of the screw overlapping the opposite sides of the slot, and serving to hold the spring in place. This necessitates the making'of a spring of a peculiar shape for thispartieula'r purpose, andis a matter of considerable expense, as well as of inconvenience, in the matter of replacement or removal of the spring. I

The invention consists in applying the lifting-spring to the detent-lever in such manner as to'be' enabled to employ for such springi a piece of theordinary hair-spring now universally employed in watches-and chi-o nometers, as well as to enable it to be applied or inserted in place, and adjusted longitudinally very easily'and expeditiously, one particular advantage of my invention being the ease and ecouomy'with which a brolreusprihg may be replaced. I

The invention is accomplished by making a saw-kerf, or narrow slot, in the upper. face of the freeend of the detent-lever, of a sufiicient depth to nearly receive the width of the spring, a screw being passed into the' metal, immediatelycontiguous to the slot, and so that the head of the screw shall overlap and bear upon the upper edge of the spring, and, by its pressure :thereupon, retain it securely in place, at the same time, when. occasion requires, allowing the spring to be adjusted longitudinally with much greater accuracy and nicety than if it were secured in place by a wedge.

By referring to the drawings abovelmention'ed, as accompanying and making part of this specification,it willvbe seen that a denotes the detent-l ever of a chronometer-escapement, bits pivot or axis, and c its detent, such being constructeda'nd applied inthe ordinary manner. V

In carrying out 'my invention, I out within the face of the outer or free end of the detent-lever a, or an enlargement, d, thereof, a narrow saw-kerf, e, of a width suflicient to easily receive the' thickness of the featherspring, and of a depth slightly less-than that of such opening.

' I furthermore insert within the metal of the enlargementor end, d, of the lever a, and in close proximity to the saw-kerf e, a screw, f, the head of such screw, as before observed, overlapping or spraining the saw-kerf,

-'Tl1'e.feather-springis shownat g, being, in this instance, a. narrow strip .or. ribbon, out from an ordinary hair-spring, the said spring being inserted, at one end, within the saw-kerf e,.aud retained securely in place therein by the downward pressure of the-head of the' screw f upon it, the; spri g extending along between the pivot and-detect of the lever'u, as shown in the drawings.

To move the spring in either direction longitudinally within its slot, or to enable it to be removed entirely therefrom, it is only necessary to give a partial turn of the'scr'ew in the right direction, which freesits'pressure upon the-spring. v 5 I The above. description will readily. explain the nature and advantage of lily-invention to intelligent persons, and particularly to w atchmak ers, to whom' this"'s pecification' is'chieiiy addressed, and whowill appreciate its advantages,-which, though to a-casual observer would appear slight, arerin reality, owing to the delicate nature of the construction of a watch, of great importance.

- the purpose as hefore explained.

In fixing the ordinary hair-spring to its post, the employment of the principal idea of my invention may be found of great value, as the liniformcar've'or arc of the spring may be maintained'b of a. corresponding-sized are 6f a'clrcle with that'descrihed by the spring.

I claim as my inventiony forming the saw-kerf The mode, substantially as herein sho'ivn an'd deseribeiof applying the feather or the hair-spring of a' chronome'ter or watch-e'seapement, that is, by means Of the saw-kerf e and sepewfisubstantially in manner and for h 1 GEO. P. READ. Witnesses:

EDWARD GRIFFITH, C. W. BALDWIN, Fminsmcx 011mm. 

